1. Field of the Invention
This invention relates to a fire extinguishing device for an oil burner and more particularly to a device capable of instantaneously and surely accomplishing the fire extinguishing of an oil burner such as an oil space heater or the like only by lowering a wick of the oil burner.
2. Description of the Prior Arts
Conventionally, the fire extinguishing operation of an oil burner such as an oil space heater or the like has been generally conducted in such a manner that a wick of the burner is lowered into a wick receiving chamber thereof to gradually reduce the generation of vapor of fuel oil such as kerosene from the wick and to gradually reduce flames, to thereby allow the fire extinguishing of the oil burner as long as 100 to 250 seconds. Such conventional fire extinguishing operation has been widely used because it allows fuel oil vapor remaining in a wick receiving the chamber to be perfectly burned, to thereby substantially reduce the generation of bad odor from fuel oil vapor during the operation. However, such conventional operation does not permit the fire extinguishing of an oil heater as short as ten seconds in an emergency such as an earthquake.
Two devices have been conventionally employed which instantaneously accomplish the fire extinguishing of an oil burner by lowering a wick into a wick receiving chamber. One of such conventional devices is disclosed in Japanese Utility Model Publication No. 47225/1974. The device disclosed in the Japanese utility model publication is constructed to instantaneously conduct the fire extinguishing operation of an oil burner by means of an air introduced into a wick receiving chamber through small holes which are provided around the outer wall portion of the wick receiving chamber above an upper end of a wick lowered into the wick receiving chamber, the wick receiving chamber being communicated through the small holes to an ambient atmosphere when the wick is lowered into the receiving chamber. During the combustion operation, an air is not substantially introduced through the holes into the wick receiving chamber, because the wick substantially closes the holes; thus, the existence of the small holes does not adversely affect the combustion of fuel oil in a combustion chamber positioned above the wick receiving chamber. When the wick is lowered into the wick receiving chamber in order to conduct the fire extinguishing operation, an air is introduced through the small holes into the upper space portion of the wick receiving chamber to form an air phase between the vapor phase of fuel oil generated from the wick lowered into the lower portion of the wick receiving chamber and flame within the combustion chamber. Thus, the air phase interrupts the communication between the flame and the fuel oil vapor to accomplish the fire extinguishing of the oil burner. However, such conventional device has a disadvantage of generating bad odor because a gas of a high temperature within the combustion chamber goes up through the chamber to cause an air to be introduced through the small holes into the combustion chamber, so that fuel oil vapor adjacent to the wick is carried on the air to the combustion chamber of a high temperature and is subjected to thermal decomposition. An additional disadvantage encountered with such conventional device is that fuel oil vapor within the combustion chamber ignites outside the oil burner by outwardly leaking from the small holes, or a great volume of air is introduced through the small holes into the combustion chamber to lower a temperature of the combustion chamber and to cause fuel oil to be burned in the portion of the combustion chamber adjacent to the wick receiving chamber; so that an oil tank of the burner or the wick receiving chamber is heated to a high temperature.
The other conventional device is disclosed in Japanese Utility Model Publication No. 18736/1977 which instantaneously accomplishes the fire extinguishing of an oil burner. Such conventional device is constructed in such a manner to blow out a wick by means of a blast generated due to the ignition of fuel oil vapor stored in a preliminary chamber provided around a wick receiving chamber immediately after the wick has been lowered into the wick receiving chamber, to thereby instantaneously achieve the fire extinguishing of an oil burner. In such device, the flame of the wick is drawn into a gap between inner and outer walls of the wick receiving chamber when the wick is lowered, and then, the flame ignites and explodes the oil vapor within the preliminary chamber to produce a great volume of pressurized gas. The pressurized gas jets from the preliminary chamber through small holes provided at the preliminary chamber to the gap between the inner and outer walls of the wick receiving chamber to expel the flame of the wick, to thereby accomplish the fire extinguishing of the oil burner. However, such conventional device has a disadvantage of generating bad odor, because unburned fuel oil vapor and undecomposed gas contained in the jetting gas produced due to the explosion of fuel oil vapor within the preliminary chamber are introduced into the combustion chamber of a high temperature and are subjected to thermal decomposition. In addition, the conventional device has another disadvantage that it is difficult to constantly keep fuel oil vapor within the preliminary chamber in the explosive range; and, when fuel oil vapor within the preliminary chamber is not exploded, it is almost impossible to instantaneously accomplish the fire extinguishing of an oil burner.